High quality screw dehydrator

In the early days, the shape of the stacked screw filter is not like this, its predecessor is a food machine, is a filtering machine, called a screw filter, is a shaft of the expanding screw and the outside of the filter.First appeared in Germany in the 1960 s, and then in the former Soviet union, Sweden, the United States and other countries also have to make this kind of filter, and the earliest application in oil and fish meat after grinding squeeze dewatering, fish, shrimp waste filter, it is the purpose of the moisture of filter residue in aquatic products, convenient for reprocessing of aquatic products later.When filtering fish, shrimp and other materials, it is found that at the beginning of filtration, the feed is pushed by a shaft screw, and the water in the material is squeezed out from the filter net wrapped around the screw.Filtering but after a period of time of extrusion filtrate stopped out, after extrusion materials dry cake nor from discharge outlet discharge, through the study found that the main reason for the failure is the material concentration increase, because the mesh structure is fine holes, these holes are particularly vulnerable to the material of the congestion, and finally results in the decrease of filtration efficiency, cannot complete filtering, can only continue the filter to clean up after downtime.

The seventh part of sludge treatment in sewage plant - the stack screw extruder

With the development of spiral filtration technology, a relatively new filtration structure, such as gate mesh structure and moving fixed ring filter structure, appeared in 1970s in Germany and other European countries to avoid the problem of blocking the holes in the mesh.Among them, the moving and fixed ring filter mechanism is to cover multiple ring pieces on the screw shaft. The ring pieces are divided into two types: fixed ring piece and movable ring piece, which also become static ring and moving ring.Static ring and the spacing between ring assembly, formed the certain filtering space between the ring plate, by mutual friction between the ring and static ring, as well as to the material static ring in the process of pushing extrusion and ring, so that the spiral push materials, has been driven is greater than the effect of friction force, improve the effect of the material of the filtration separation, especially the ring and static ring filter gap in constant friction between the clean, so as to avoid the high viscosity material blocking phenomenon of the filter hole of original structure.In this way, we have evolved into the common form of stacked screw dehydrator.

The seventh part of sludge treatment in sewage plant - the stack screw extruder

Because of its high viscosity of municipal sludge and oily sludge, other machine in the process of high viscosity of sludge dewatering, extrusion, centrifugal to constant adjustment and adaptation, and fold the screw type dryer from the predecessor is the viscosity of the material cause of mechanical filter, fold the screw type dryer in recent years, especially in sludge dewatering, and other industrial processes, and other fields has been widely used.The screw dehydrator is also known as the screw dehydrator, which USES a rotating shaft screw to push the sludge in the chamber composed of moving ring and static ring, and then squeezes the sludge to complete the process of sludge dehydration.

The seventh part of sludge treatment in sewage plant - the stack screw extruder

The dehydration process of the stacking screw dehydrator is divided into three processes: concentration, dehydration and self-cleaning. After the sludge is promoted by the sludge pump, it is mixed with flocculant in the mixer in the front section of the stacking screw dehydrator (or reentry) and then enters into the stacking screw cavity through the sludge distribution pipeline for extrusion dehydration.According to the different functions of the screw stacking machine, the cavity is divided into two parts: concentration part and dehydration part.After the sludge into the chamber is concentrated by gravity in the concentration part, it is transported to the dehydration part by a spiral push. In the process of moving forward, with the gradual decrease of the filter joint and pitch, and the blocking action of the back pressure plate, great internal pressure is generated and the volume is continuously reduced to achieve the goal of full dehydration.